This invention pertains to computers and other information processing systems and, more particularly, to an air moving device such as a fan or blower that includes a back flow damper that is functional in either of two orientations; non-inverted and inverted.
High reliability in computer systems, such as server blade system, can be achieved through the use of redundant components including redundant cooling devices, such as fans, blowers and other air moving devices. In one design for a server blade system, air is moved through the various components of the system and, ultimately, into a plenum positioned at the back of the main chassis CH1 and located between two blower units. The position of such a plenum is visible in FIG. 1 as the space between the two blowers BL1 and BL2.
Since air is moved through the server blade system of FIG. 1 by up to two blowers BL1 and BL2, and since both blowers draw air in from the same plenum, the failure of one blower would result in the back flow of air through the failed blower and into the plenum. Since the back flow of air through the failed blower is a low resistance path, while the preferred air flow through the system components is a higher resistance path, the failure of one of the blowers would result in a significant drop in the air flow rate through the system components; as the majority of the air flow is drawn through the failed blower. The solution to this problem is to place a back flow damper on both blowers, such that if one of the blowers fails, the dampers on the failed blower will close to prevent back flow through the failed blower.
Since blowers BL1 and BL2 are mounted one above the other, and since they both draw air in from the same plenum, which is located between the two blowers, then one blower must be inverted relative to the other blower such that the air inlet of both the upper and lower blowers is adjacent the air intake plenum in the server blade chassis. Accordingly, the invention described below is an air moving device that can function in either of two orientations, such that it can be installed in the lower blower bay of a server blade system, or inverted and also installed in the upper blower bay. More importantly, this air moving device includes a back flow damper that functions in both orientations.
Briefly, the invention is an air moving device assembly including a housing having an air inlet and an air outlet. The air moving device assembly has a first orientation wherein the air inlet is oriented in a first direction, and a second orientation wherein the air inlet is oriented in a second direction substantially opposite the first direction. An air moving device is located within the housing for moving air from the air inlet to the air outlet. A back flow damper assembly is positioned over the air outlet and includes: 1) a first end baffle pivotally attached to a first end of the back flow damper assembly; 2) a second end baffle pivotally attached to a second end of the back flow damper assembly, the second end being substantially opposite said first end, and 3) at least two middle baffles pivotally attached to the back flow damper assembly between the first and second end baffles. When the air moving device assembly is in the first orientation and in the event of a failure of the air moving device, the first end baffle and the two middle baffles cover the air outlet to prevent the back flow of air through the air outlet, and the second end baffle pivots away from the air outlet so as not to block the back flow of air though the air outlet. When the air moving device assembly is in the second orientation and in the event of a failure of the air moving device, the second end baffle and the two middle baffles cover the air outlet to prevent the back flow of air through the air outlet, and the first end baffle pivots away from the air outlet so as not to block the back flow of air though the air outlet.